In certain circumstances it is desirable to isolate from a use environment the electrical contacts and wires within an electrical connector assembly. One such circumstance arises when electrical connectors are employed in aviation. Exposure to extremes of temperature, pressure, or humidity, and frequent cycling between those extremes (e.g., with each takeoff, climb, cruise, descent, and landing) can lead to corrosion or other degradation of the electrically conductive parts of the connector. In certain conventional electrical connector assemblies a resiliently deformable wire grommet is employed to seal around one or more wires that enter the connector assembly. It may be desirable to provide improved or enhanced sealing around the wires by a wire grommet.
An example of a conventional connector assembly (arranged according to an SAE AS50151 standard in the example shown) is shown in FIGS. 12-18 and comprises a substantially rigid front connector body 30; a substantially rigid rear connector body 20; a resiliently deformable wire grommet 10; and a threaded nut 40. The rear connector body 20 (also referred to as a connector accessory or as a connector backshell) has a rear axial passage 22 therethrough; the front connector body 30 (also referred to as a plug connector body in a plug-type connector assembly, or as a receptacle connector body in a receptacle-type connector assembly) has a front axial passage. When the connector assembly is connected to one or more wires 90 (three wires 90 in the examples shown, with spaces for more; any suitable number of one or more wires can be employed) and assembled, a resiliently deformable wire grommet 10 is positioned within the front axial passage and the wires 90 pass through the rear axial passage 22 and through corresponding wire passages 12 of the grommet 10. An insulating body 38 of the front connector body 30 is structurally arranged so as to hold one or more electrical contacts 92 that are each connected to a corresponding wire 90. In the examples shown the electrical contacts 92 are pin contacts; in other examples the contacts are socket contacts. The wire grommet 10 serves to isolate the electrical contacts 92 and the conductive cores of the wires 90 from a use environment.
The front connector body 30 of the conventional connector assembly has triangular teeth 39 arranged just outside the rear end of the front axial passage; the rear connector body 20 of the conventional connector assembly has mating triangular teeth 29 arranged around the front end of the rear axial passage 22. The rear connector body 20 of the conventional connector assembly also can have a so-called web 29w between the teeth 29 but not extending beyond the tips of the teeth 29. The teeth 29 and 39 engage one another when the front connector body 30 and the rear connector body are assembled, but no portion of the teeth 29, the web 29w, or the connector body 29 extends forward into the interior of the front connector body 30 (i.e., forward beyond base portions of the teeth 39).
The nut 40 includes a central opening and internal threads 44. The nut 40 is structurally arranged so as to receive through the central opening a rearward portion of the rear connector body 20 and to obstruct rearward movement of the forward portion of the rear connector body 20 through the central opening. In the example embodiment shown, an outward circumferential flange 28 of the rear connector body 20 is too large to pass an inward circumferential flange 46 of the nut 40. A rearward portion of the front connector body 30 includes external threads 34 that engage the internal threads 44 of the nut 40. Tightening of the nut 40 threadedly engaged on the rearward portion of the front connector body 30 (via threads 34/44) results in forward movement of the nut 40 and the rear connector body 20 toward the front connector body 30; fully tightening the nut 40 results in fully engaged assembly of the connector bodies 30 and 20 and engagement of the teeth 29 and 39.
The wire grommet 10 has a substantially cylindrical outer surface and one or more axial wire passages 12 therethrough. Each wire passage 12 includes two or more wire-sealing segments 12a (also referred to as glands) and an intervening, transversely enlarged, internal chamber 12b between each adjacent pair of wire-sealing segments 12a along each wire passage 12. Each wire-sealing segment 12a is sized and shaped so as to (i) enable a corresponding wire 90 to be inserted through the corresponding wire passage 12 and (ii) form a seal around the corresponding inserted wire 90. A rear portion of the wire grommet 10 extends rearward beyond the rear end of the front connector body 30 and is received within a rearward-tapered forward segment 24 of the rear axial passage 22. The nut 40 is tightened and the front and rear connector bodies 30 and 20 are fully engaged (by engagement of the teeth 39 and 29), the tapered segment 24 radially compresses the protruding rearward portion of the wire grommet 10 and only the hindmost wire-sealing segment 12a of each passage 12.
The introduction of lighter-weight wires with spiral tape insulation has been beneficial for overall weight reduction in avionics applications. However, those wires tend to have an oval or elliptical cross section and an uneven outer insulator surface where adjacent tape windings overlap, resulting in inadequate sealing of the wires by conventional connector assemblies. Inadequately sealed connectors are subject to more rapid corrosion, resulting in premature connector degradation or failure and requiring more frequent repair or replacement. It would be desirable to provide a connector assembly that provides improved sealing, particularly around wires with non-circular cross sections or uneven outer insulator surfaces.